You can try the vitamin C method like I showed earlier in the video, but blue is seriously so stubborn that it probably won’t be enough. The next thing you can try is a hair dye stripper like L’Oreal Color Oops and see if that’ll do the trick. A bleach bath would be the next step to take if you can’t get either of those to work, but try those first and see if you can get that blue out!
I can already verify that the vitamin c does not do much to dark blue hair.
When I used it on my hair when it was teal and dark blue, it was definitely not as effective as it is with other colors I’ve used it on like pink, green, and literally every color of the rainbow because I used it to fade out my rainbow hair. Blue is the most stubborn, but you can get some of it out with vitamin c. I crushed up hella tablets and mixed it with the generic version of head n shoulders shampoo and scrubbed and scrubbed my hair. I find that scrubbing is a key part with the blue as it doesn’t come out easily on its own. I’ve also found that leaving this treatment in your hair overnight with a bag or showercap over it is a great way to keep it working as long as possible. Do this a few nights in a row and it’ll have an impact on the blue. It won’t get rid of all the color like it could with anything besides blue but it will help!